This invention relates to a pile driving apparatus and method.
Piles are typically driven using a lead structure suspended from a crane or the like. The lead structure includes a passage within which the upper end of the pile is received, and a hammer is mounted for up and down movement to the lead structure. The hammer is raised upwardly within the lead structure by any satisfactory system, such as one utilizing compressed air and steam, diesel fuel or hydraulic oil, and is then allowed to fall downwardly on the pile, for driving the pile into the ground.
The lead structures in prior art pile driving systems are generally bulky and difficult to maneuver when driving piles in tight spaces. Further, many pile driving systems require use of auxiliary equipment, such as a compressor, which must be hauled to and from the site. Such systems are also relatively expensive, in that the lead structure is a fairly complicated piece of equipment and incorporates a number of fittings for the hammer raising system.
It is an object of the present invention to provide a pile driving apparatus and method which is extremely simple and relatively inexpensive in its construction and operation. It is a further object of the invention to provide a pile driving system adapted for use in tight spaces by eliminating the need for a bulky lead structure.
In accordance with the invention, a pile driving method includes providing a crane having a line adapted for lifting and lowering, and connecting a hammer directly to the line, with the hammer including guide structure. The hammer guide structure is engaged with the pile, and the hammer is reciprocated in an up and down manner by operation of the crane while the guide structure is maintained in engagement with the pile. In this manner, the pile functions to guide the hammer during up and down movement of the hammer in response to operation of the crane. The guide structure is in the form of a guide member which extends from the hammer. In one form of the invention, the pile includes an axially extending passage, and the hammer guide member is engaged within the passage of the pile. The guide member is maintained within the passage in the pile during up and down movement of the hammer. The guide member is provided with a cross-section corresponding in shape to the passage of the pile and in close tolerance to the internal walls of the pile defining the passage, for preventing lateral movement of the hammer relative to the pile as the hammer is being moved upwardly and downwardly in response to operation of the crane. In the event the passage of the pile is larger than the guide structure, an auxiliary guide structure can be mounted to the guide member, with the auxiliary guide structure having a shape corresponding in cross section to that of the pile passage. The step of maintaining the guide structure in engagement with the pile can be carried out with the assistance of a flexible member, such as a chain, interconnected between the hammer and the pile for preventing the hammer from being raised relative to the pile an amount sufficient to disengage the guide structure from the pile. The hammer includes an opening within which one end of the chain is engaged, and the other end of the chain is mounted to a collar assembly mounted to the pile.
The invention further includes a unique and simple arrangement for mounting the hammer to the pile, and also for driving a battered pile, i.e. a non-vertical pile, into the ground.
The invention further contemplates a pile driving apparatus substantially in accordance with the foregoing summary of the pile driving method of the invention.
Various other objects and advantages of the invention will be made apparent from the following description taken together with the drawings.